Electronic organ with chiff



July 25, 1967 1. B. BROMBAUGH 3,333,042

' ELECTRONIC oRGAN WITH GHIFF Filed Oct. 2, 1963 4 Sheets-Sheet l July 25, 1967 Filed OCT.. 2

J. B. BROMBAUGH ELECTRONIC ORGAN WITH CHIFF N075' TE 4 Sheets-Sheet 2 (ll/FF vars 6472-' (ll/FF 61475 ,w52 (ll/FF ATE ggg

Jaw 6ta/164060 INVENTOR.

July 25, 1967 J. B. BROMBAUGH 3,333,042

ELECTRONIC ORGAN WIYTH CHIFF AFiled oct. 2, 1963 4 sheets-sheet :s

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The present invention relates generally to electronic organs and more particularly to organ systems having provision for addition of chi components to certain of the notes of the organ. Perfection in electronic organs subsists in the minds of some musicians in duplication of total characteristics of pipe organs. Pipe organs inherently generate certain transient sound eects, especially at the initiation of each tone. These eects involve (1) a build up and decay of a spectrum of harmonics, constituting a tone, (2) an audible tonal content occurring only vat initiation of a note, and which may be harmonically or inharmonically related to the steady state spectral components, but which does not derive from the tonal build up, having its own frequencies and its own envelope shape. The latter eect is called chi. Since chi generation involves production of tonal components inharmonically related to the accompanied tone, as well as a different wave envelope, the problem of incorporating chi into electronic organs on an economic basis involves utilizing to the maximum extent organ components which are present in any case for tone production, so that the addition of chi does not add unduly to the cost of the organ. It is entirely possible, for example, to provide chi circuits which are separate and apart from the organ tone circuits and to key these by means of separate keys and key switches. In view of the large number of tones in an electronic organ of sufficient sophistication to justify the inclusion of chi at all, such an expedient is not economically practical.

It is an object and feature of the present invention to provide an organ which includes chi and in which the -already existing components of the organ are largely made available as chi generators.

Briey describing a preferred embodiment of the invention, the tone generators of the organ are in the form of square wave oscillators. The square waves provide an array of harmonic frequencies associated with each tone. suitable for ltering to form the Various tone colors of an organ. Should the array of harmonics prove insuicient because of the symmetrical wave shape of the generator outputs, the square waves may be `.added in appropriate frequency and amplitude relations to form triangular waves, and these can be used as basic tone materials. It is further conventional, especially in sophisticated organs, to transfer the basic wave shapes provided by the oscillators to headers through gating circuits, keyed on and o by means of key switches. In -accordance with the present invention keying circuits are incorporated, in electronic organs, each of which is provided not only with a tone signal but also with a chi signal deriving from a sepa-rate tone oscillator. The separate oscillator may be one of the oscillators already present in the organ. Since the organ uses continuously running oscillators which are gated through to the header, and continuously running chi circuits which are also gated through the same or la dierent header, each key switch may, by means of a single pair of contacts, control both the tone gate and the chi gate. By means of this device not only is the cost of switching maintained at a minimum but no possibility exists of mistiming the chi with respect to the main tone. In order to simulate chi successfully the chi must be heard before the mai-n tone-is heard and there must be time overlap of the chi with the main tone, during the rise time of the main tone. The key initiates both tones i.e. note and chi, simultaneously, but the keying circuits are so arranged ICC that the chi is passed through the gates in considerable amplitude during the rise time of the main tone, so that the chi is clearly audible initially, and while the chi still subsists, the main tone gradually is brought into peak amplitude and the chi tone itself decays to zero. Accordingly, a delicate timing relationship exists which would be difficult to solve if the chi gate and the main tone gate are controlled by separate contacts of key switches.

Y It is, accordingly, a broad object of the invention to provide a gating circuit for gating the main tones and chi tones to a header wherein essentially separate gates are employed for the chi and the main tone, both gates being differently keyed, however, by gate wave generato-r circuitry responsive to closure of a single switch, i.e. to application of a single keying voltage.

It is a further object of the invention to provide a novel organ having provision for deriving chi from tone sources of the organ which are in any event available to produce organ tones and wherein the tone sources are constituted of continuously running oscillators.

A further object of the invention resides in the provision of a novel gating circuit capable of gating through an A.C. signal in accordance with two diverse wave shapes, one of which starts at zero and builds up to `a maximum and decreases to zero in a relatively short time, while the remaining wave is building up from zero to a steady state value. The above and still further features and objects of the invention will become clear upon consideration of the following detailed description of various embodiments of the invention, especially when takenin conjunction with the accompanying drawings wherein: n

FIGURE 1 is a block diagram of an organ system, according to the invention.

FIGURE 2 is a block diagram of a modification of the system of FIGURE l, employing separate chi gates and note gates, whereas the system in FIGURE 1 employs a 'single gating circuit, including gates for both chi and notes.

FIGURE 3 is a further modification of the system of FIGURE 2, wherein provision is included for incorporating noise into the chi sounds.

FIGURE 4 is a schematic circuit diagram of a gating circuit employable in the systems of FIGURES l to 3.

FIGURE 5 is a wave form diagram showing certain charging lcurrents and certain voltages, occurring in the gating lcircuit of FIGURE 4, and

FIGURE 6 is a schematic circuit diagram of a further gating circuit employable in the systems of FIG- URES 1-3. f

Referring now -more particularly to the accompanying drawings, in the system of FIGURE 1, the lead 10 denotes a common ground lead for a series of continuously running tone oscillators 11, 12, 13, 14. In the usual organ a very large number of oscillators are present, but to lsimplify the presentation only yfour oscillators have been shown, which are those generating the tone F31?, F3, Clit, C1, respectively. The tone oscillators 11-14, inclusive, are connected in cascade with gates 15, 16, 17 and 18, respectively. The `gates may be normally closed and are placed in open condition in lresponse to keying signal. Keying circuits for the gates 15-18, inclusive, are 19, 20, 21 and 22, respectively. A lead 23 provides a fixed D.C. Voltage and key switches 24, 25, 26 and 27 proceed from the lead 23 to the keying circuits 19-22, respectively, so that closure of any one of the keys results in application of D C. voltage from the lead 23 to that key, causing the keying circuit to turn on the associated gates. The keying circuits incorporate wave shaping devices, so that in response to the steady D C. voltage on the lead 23, each keying circuit provides to its associated gates a pair of wave shapes, one appropriate for gating chi and the other appropriate for gating the tone itself.

fto the `gate 18 and also a chiii gating wave which is applied to the gate 16, which is associated with the oscillator 12 generating the tone F3. The tone F3 is 29 semitones above the tone C1 and is thus .at a frequency appropriate Ifor the generation of chifi. The gates l15-18 are connected to appropriate headers, generally indicated as 30 and 31, which lead to appropriate arrays of tone color filters 32, 33 and the latter leads to an output circuit, 34, normally constituted of ampliers and loud speakers.

The gate 17 passes the tone signal Clit from the oscillator 13 in response to closure of key 26 and consequent generation of the tone keying wave by keying circuit 21. The latter also provides chiii keying signal to gate 15. Accordingly, the note Clit is acompanied lby transient tone deriving from the generator 11 of the oscillator 11, which generates tone F31?. Thus the same keying circuit 21 which gates open the gate 17 also supplies a gating voltage to the gate 15 which is of appropriate wave shape to sound like chiii. It will be noted that any one of the gates, as 16, for example, may be required to pass chifi (in association with tone C1), also may |be keyed on by the key 25 and accordingly rnay be required to pass tone signal F3. This implies that, if the notes C1 and F3 were ,played simultaneously, the one gate 16 would be subject A1y to the chifi wave form and the main note wave form.

It is found that the two tones ldo pass through the organ although in this circumstance the chifi tone may be masked. Since, however, the normal playing of music involves complicated fingering, and the playing of plural notes simultaneously at most times, at least most of the tones will always be provided with chifi, and if an occasional tone has its -chiii masked, this will not detract |from the quality of the music, even for the skilled musician. The chifi control line 35 applies variable control voltage to the keying circuits to control the duration and amplitude of the ychifi gating waves and is to turn them ofi, as will appear hereafter.

Referring now to FIGURE 2 of the drawings provision is made for separate note gates and chiii gates. VThe oscillator 12, for example, includes the note gate 40 and the chifi gate 41 .both connected in parallel to the oscillator 12. The note gate 40' is controlled by a keying circuit 42 while the chili gate 41 is independently controlled in response toa keying circuit 22 ofthe key switch 27. Thereby the closure of the key switch 26 is accompanied by playing of the note 'Clit through the note gate 45 as well as by playing of a chifi note at frequency F3# through chifi gate 46. Playing of the note C1 is accompanied by playing of the note F3 with a chifi wave form through the chili gate 41. Each note of the musical scale then includes a key switch in the keying circuit, and gencrates a key wave for a note gate associated with the keyed oscillator in the chili gate associated with an oscillator 29 semi-tones above the main tone pitch.

The chili gates, identilied as 46, 41, 47 and 48 all lead to a common chifi header 50. The chifi header proceeds to chili filters 51 and 52 each of which may consist of one or more filters as required to shape the square wave output of the tone generators to have a sound appropriate for chii. The chifi filters are connected in parallel to an output circuit appropriate for an organ and including, usually, ampliiiers and one or more loud speakers, The note gates which are identified as 40, 54, 45 and 49 are connected to a further tone bus 60, which in turn proceeds to tone color filters `61, 62, appropriate to the organ in question, the tone color filters 61, 62 being connected in parallel to the output source 53.

The system of FIGURE 3 generally duplicates the system of FIGURE 2 except in that the system of FIG- URE 3 includes noise sources 70', 71 and chiti oscillators in addition to note oscillators. 70 and 71 represent noise sources and 72, 73 represent chili tone sounces, and 13, 14 note tone sources. Sources 72, 73 in the system of FIGURE 3 are not note tone oscillators, but are auxiliary to the note oscillators. Resistors 75, 76 serve to combine t-he outputs of the signal sources as 70, 72 into gate 47. The inclusion of separate chii oscillators 72, 73 renders possible the improvement of chiii efiects by specifically designing the oscillators 72, 73 for their intended purpose in terms of tonal components and basic frequency. It may occur, in the case of an organ of the type illustrated in FIGURE 2, that no available tone generator can provide a chili frequency. Such a diiculty cannot occur in the system oi FIGURE 3.

It occurs, systems such as those in FIGURES l and 2, that for the higher tones of the organ, no still higher tones are available from which chiff can be derived. This problem may be solved in a practical organ as a compromise measure, by utilizing relatively low chiff frequencies, i.e. instead of using tones 29 semi-tones above the main tone as a chifi source, lower frequency oscillators are employed for the purpose or chili is omitted for high rnotes lfor which appropriate generator frequencies are not available. Moreover, two tone oscillators may be associated with the chiii si-gnal oscillator, so that the chili frequencies for two adjacent notes are the same.

Of course, in such a system additional chili oscillators may lbe provided as tone oscillators become unavailable for the high frequency notes, but as a practical matter, at the high frequency end of the scale `frequency pitch fdiscrimination becomes poor and the fact that the chifi is not approximately 51/2 times the frequency of the main tone, as it should be, or is omitted entirely, becomes of no great importance. The noise generators 70, 71 are supplied with power kfrom the line 76a which may be provided with a switch 77 in order to disable the noise sources at will, so that the chili generated by the system of FIGURE 3 includes or excludes noise, at will. By the same token, if switch 78 is opened the chiii will consist of noise alone, without chifi tone.

In the gating circuit of FIGURE 4, a source of negative D.C. voltage (--100 v.) vis connected in series with -a switch 111, three resistances 112, 113, 114 (330K each), and the control point 115 of a diode gate 116. The junction of resistances 113, 114 is connected to ground through -a capacitor 117. The diode gate 116 utilizes two diodes, 118 and 119, having their cathodes connected to control point 115. Square wave tone signals 120 (i1/2 v.) are applied to the terminal 121, connected to the anode of diode 118. A small output resistance 122 is connected between the anode of diode 119 and ground. 123 is an output lead for deriving voltage existing across output resistance 122'.

On closure of switch 111, negative voltage builds up approximately exponentially (assuming only the portion of the circuitry of FIGURE 4 hereinabove specifi- -cally described) across capacitor 117 That voltage appears at control point 115, minus any drop occurring in resistance 114, and gradually biases gate 116 on, so that areplica of signal 120, of gradually increasing amplitude, flows through output resistance 122, and becomes available on output lead 123.

Connected between ground and the junction 125 of resistances112 and 113 seriatim are a diode 127, a capacitor 128 .and a capacitor 129, the cathode of diode 127 being connected directly to point 125. On closure of switch 111 the capacitors 128, 129 charge exponentially through diode 127 and resistance 112. The new voltage applied-to the circuit of capacitor 117 is thus more complex than was above indicated for the simple case, in that the voltage .as seen by capacitor 117 is exponential, on closure of switch 111 applied. The rise of voltage at control point 115 is thus only approximately experiential.`

trol voltage at control point 115 and hence proceeds as a function of time from 0 v. to some maximum value perhaps .05 volt.

A relatively high resistance, 130, is connected at one terminal to the junction 131 of capacitors 128, 129, and at its other terminal to the slider 132 of a potentiometer resistance 133, connected between a positive voltage terminal 134 (-1-100 v.) and ground. Connected between junction point 131 and ground is a diode 135, conductive to positive voltage. From junction point 131, a resistance 136 (330K) extends to control point 137 of diode gate 138, which duplicates the gate 116. The diode 135 clamps point 131 to ground potential, in response to application of positive potential, but permits point 131 to go negative. l

As long as switch 111 is open, then, control point 137 is at ground potential and any input signal 140, or 141 (which are applied selectively), cannot control current flow through the gate 138. The signal 140' may be assumed to be .a replica, except for frequency, of signal 120, i.e. to be a square wave of :t1/2 v. amplitude. The diodes of -gate 138 are denominated 143, 144, its output resistance 145, and its output lead 146.

When switch 111 is closed, an exponentially decreasing current Hows from ground, through capacitors 129, 128, diode 127, resistance 112, and switch 111 to terminal 110. Because this current is initially greater than the current from slider 132 into resistor 130, the diode 135 ceases conduction, since its anode goes negative, and capacitor 129 charges, with the voltage at point 1311 proceeding in a negative sense. As the current through the branch containing .capacitor 128 decreases, the charge rate on capacitor 129 also decreases until the time when the two opposing currents are equal. At this time, the charging of capacitor 129 stops and the maximum negative voltage appears across capacitor 129. After this time, the current flowing into capacitor 129 from resisto-r 130 is greater than the current flowing out of capacitor 129 into capacitor 128, hence capacitor 129 4begins to lose its previously acquired negative charge and the voltage at point 131 proceeds back toward zero. When the voltage at point 131 reaches zero and tends to go positive, diode 135 conducts, which reduces the current to capacitor 129 to zero and the voltage at 131 remains clamped at zero.

The peak value and time duration of the voltage pulse occurring at point 131 depends on the current flowing through resistor 130 and may be varied by changing the voltage at slider 132. Because the voltage at point 131 controls the level of signal passed by gate 138, variation in the voltage at slider 132 may be used to aect the amplitude and duration of the signal passed by gate 138. Typically 100 volts at slider 132 is capable of rendering gate 138 inoperative when key 111 is closed, thus giving no chi effect. Reduction of the voltage at slider 132 to 50 volts provides a gating Wave suitable for producing chi eects in musical passages where the chi producing register is used alone, i.e. without other tone colors. By further reducing the voltage atslider 132 to 25 volts, chi of greater amplitude and longer duration is produced which is audible when other registers of the electronic organ are used together with the chi producing register.

The charging currents which generate the chi gating wave, are illustrated in FIGURE 5, wherein curve A shows the negative charging current into capacitor 128, due to the voltage at terminal 110. Onclosure of switch 6 i 111, to a first approximation, only resistance 112 limits charging current. Hence the initial value of current is 330K; and the current decays exponentially to zero. The charging current for capacitor 129 is shown at B. When switch 111 is closed, negative current to capacitor 129 immediately assumes a value less thanthat into capacitor 128, partly because of resistive paths around the capacitor, i.e., 130, 133, but primarily because capacitor 129 is subjected to positive current flow through resistance 130 (see curve C). In due time, i.e. at point E, these two current flows, one negative and the other positive, are equal, and net flow is zero.

Voltage at this time, at point 131, is negative. Current into capacitor 129 then -flows in an opposite sense at an increasing rate until point 131 attains zero potential. At the point F, zero potential at point 131 has been reached at which time the diode 135 clamps to ground, reducing not only the current into capacitor 129 to zero, but also the voltage across it.

Current in diode 135, indicated at G, equals zero so long as point 131 is at negative potential, but increases rapidly when point 131 clamps, to pass the current then proceeding to capacitor 129. The diode thus presents an alternate or shunt path for charging current. Diode current then continues to increase so long as charging current into capacitor 128 continues, which is for a considerable time. This occurs because capacitor 128 robs diode 135 of current through resistor 130. When the circuit becomes completely quiescent, current through diode 135 equals the voltage at point 132 divided by 560K.

The diode 127 is required in order to isolate the capacitor 128 from the capacitor 117. The latter is at -30 v. in a typical circuit while the capacitor 128, at point 150, is at about -60 v. Diode 127 blocks a discharge path from capacitor 128 into capacitor 117, when key 111 is released, and requires capacitor 128 to discharge via re-` sistance 147. The capacitor 117 is required to discharge through resistance 114. The diode 127 presents no path for current from capacitor 117, because its anode is biased by the -60 v. at point 150. Each of capacitors 128, 117 thus discharges through a path of minimum resistance, i.e. 680K for capacitor 128 and 330K for capacitor 117. Economies are eected in the system of FIGURE l, by utilizing each gate for both tone and chi frequency, where these are the same, by applying to the gate simultaneously both a chi keying signal and a note keying signal. This can be simply accomplished by connecting to the point 137 of the chi gate 138 the resistance 114', from a note keying circuit, where resistance 114 corresponds with resistance 114 in FIGURE 4, but derives from another keying wave generator. This expedient permits reduction in number of gates and in number of connections from oscillators to gate.

The pitch interval between a note and its chi is preferably twenty-nine semi-tones. Thus in an organ of 61 keys, taken for example, the lowest twenty-nine gates, pertaining to notes 1-29, where note 1 is the note of lowest pitch in the organ, will have only one input since they do not provide chi for other notes. The next thirty-two gates will each receive two inputs, in the system of FIG- URE l, one pertaining to note and one to chi. This may be accomplished as illustrated in FIGURE 4, where resistances 136 and 114 carry the keying waves required to gate 138.

To complete the system, gates 138 and sources 140` for the highest 29 keys remain to be provided. In a practical organ the sources 140 may be taken from the generators used for the higher pitched tone colors. This will provide 24 of the required sources 140 if the organ possesses a 2 foot stop, assuming the basic register having the chi eect is an 8 foot stop. The remaining five sources must be added or else the chi eect may be eliminated from the ve highest keys. An' alternate solution to this problem is to doubleup on theV frequencies used for the chi effect at these high frequencies, since the ear cannot readily discriminate at this pitch. This may conveniently be done by providing 24 gates, the lower nineteen of which operate in the circuit already shown. Each of the remaining five gates are used in a circuit controlled by two note keys, i.e. two keys control a single chili gate, the gates being modified for the purpose as in FIGURE 6. So the keys for notes #60 and #61 may control a chilr" gating circuit for oscillator #85, etc. The circuitry is explained in conjunction with FIGURE 6.

In the system of FIGURE 6 three gates, as in FIGURE 4, are controlled by two switches 150, 151, connected to a single negative lead 110. The relation of the keying circuits of FIGURE 6 is made clear by utilizing identical reference numbers for identical parts in the system of FIGURES 4 and 6, and priming the components added by FIGURE 6. The system of FIGURE 6 accordingly provides keying signal at terminals 115, 138 if switch 150 is closed, at terminals 115', 138, if switch 151 is closed, and at all three terminals 115, 138, 115 if both switches 150 and 151 are closed simultaneously.

Modications may be made in the invention without departing from the spirit of it. The invention having been described in certain exemplary embodiments, what is claimed as new and desired to be secured by Letters Patent is:

1. In an electronic organ, a gamut of tone sources, said tone sources constituting c-ontinuously running oscillators, an output device, gates associated with each of said sources for gating said tones from said sources to said output device, a keying circuit connected to each of said gates, a key switch associated with each of said keying circuits, each of said keying circuits generating paired gating `waves on closure of the associated key switch, one of said gating Waves having a shape appropriate to gradual build up of an organ tone, the other of said gating waves having a wave shape appropriate to a chili" component of a tone' and means for applying the one of said gating waves to a gate associated with a tone oscillator having a predetermined pitch and the other of said gating waves simultaneousy to a gate associated with a tone oscillator of pitch suitable for providing chiff component for said predetermined pitch.

2. In an electronic organ, a gamut of continuously running oscillators 4arranged in frequency according to a musical scale, a chili gate in cascade with each of a plurality of said oscillators, a note gate in cascade with each oscillator, an array of key switches, a keying circuit for each key switch and responsive to closure of the key switch for generating both a chiff gating Wave and a note gating wave, and means applying the note gating waves to the note gates, respectively, `and the chill gating waves to preselected one of said chiff gates selected always to provide chilir from one of said oscillators and tone from a different oscillator paired with said one of said oscillators and selectedato provide a suitable chifi component for said one of said oscillators.

3. The combination according to claim 2 and wherein said chili oscillator for each note is approximately twentynine semi-tones in frequency above the note oscillator.

4. In an electronic organ, a first continuously running note oscillator of first pitch, a second continuously running note oscillator of different pitch, a D.C. voltage source, a key switch, a keying circuit, means responsive v to closure of said key switch for connecting said D.C.

voltage source to said keying circuit, said keying circuit including means for generating a first wave form appropriate to organ note envelopes and a second wave form appropriate to chifl wave envelopes in response to application thereto of said D.C. voltage, a rst gate in cascade with said first note oscillator, a second gate in cascade with said :second note oscillator, Iand means simultaneouslyapplying said first wave form in keying relation to said iirst gate andlsaid second wave form in keying relation to said 4second gate.

5. The combination according to claim 4 wherein is provided a third gate in cascade with said second note oscillator, a further key switch, a further keying circuit, means responsive to closure of said further key switch for applying said D.C. voltage to said further keying circuit, said further keying circuit including means for generating a further wave form appropriate to organ note envelopes in response to application thereto of said D.C.

Voltage, and means applying said further wave form to said third gate.

6. An electronic organ having 1a gamut of continuously running note oscillators arranged in respect to pitch according -to a musical scale, a single key switching having only two contacts, means responsive to closure of said key switch for deriving from one of said oscillators a signal representing a musical note having no chili and from another of said oscillators a chili component of said musical note, and means combining said signal and said chiff component to form a musical note having a chili component.

7. A keying circuit, including a gate having a control point, a source of negative D.C. voltage, a switch, and series resistances, all connected in lseries to the control point of said gate, a capacitor connected between a lirst point junction of said resistances and ground, a diode having its cathode connected to another junction point of :said resistances, additional capacitors connected in series between the anode of said diode and ground, a relatively high resistance connecting said anode to ground, a source of positive D.C. Voltage, a resistance connecting said source of positive D.C. voltage to a junction of said additional capacitors, a further diode for clamping said junction of said additional capacitors to ground, said further diode having its cathode directly connected to ground, a further gate, and a resistance connecting the anode of said further diode to a control point of said further gate.

8. In combination, a capacitor having one terminal connected to a reference point, a source of positive current, a resistance in series between said source and the other terminal of said capacitor, a source of negative current connected to the other terminal of said capacitor, said source of negative current having a value decreasing as a function of time to an absolute value lower than the absolute value of said positive cur-rent from an -absolute value higher than the absolute value of said positive current, and a diode clamp shunted across said capacitor, said diode clamp having its cathode connected directly to said reference point.

9. The combination according to claim 8 wherein is further provided a further capacitor and a diode connected in series between said other terminal of 4said capacitor and said source of negative current, said diode being conductive in a forward direction -to said source of negative current.

10. The unit according to yclaim. 9 wherein is provided another capacitor having one terminal connected to said point of reference potential and its other terminal connected to said source of negative current, and additionalV resistances connecting said terminals of said another capacitor to the anode and cathode of said diode, respectively. Y

11. In an electronic organ, .a gamut of tone sources,

lators, an output device, gates associated with each of said sources for gating said tones from said sources to said output device, -a keying circuit connected to each of said gates, la key switch associated with each of said keying circuits, each of said keying circuits generating paired gating waves on closure of the associated key switch, one of said gating waves having a shape appropriate to gradual buildup of an `organ tone, the other of said gating waves having a wave shape appropriate toa chili component of a tone and means for applying the one of said gating waves to a gate associated with a tone oscillator having a predetermined pitch and the other of said gating waves simultaneously to a gate associated with a tone oscillator of pitch suitable for providing chi component for said predetermined pitch, wherein said gating wave having a wave shape appropriate to a lchi component of a tone build up more rapidly than build up of said gating wave having a shape appropriate to gradual build up of an organ tone, said last mentioned wave shapes having overlapping regions.

12. The combination according to claim 11 wherein is provided two separate buses, and means coupling chi components only to one of s-aid buses and tone components only to the other of said buses.

13. An electronic organ, having a gamut of continuously running square wave tone oscillators tuned according to the musical scale for providing tone components,

a gamut of continuously running chi oscillators, each at a frequency appropriate to provision of a chi component for one of said tone components and having a wave shape appropriate to chi sounds,

a plurality of noise sources,

separate Voltage supply buses for said chi and tone oscillators and for said noise sources,

means disabling either of said supply buses at will,

an array of chi gates and noise gates,

an array of tone gates,

an array of key switches, and

means responsive to each of said key switches for concurrently rendering conductive one of said tone gates and the appropriate one of said chi and noise gates.

14. The combination according to claim 13 wherein is provided a tone header and a chi and noise header,

means connecting all said tone gates to said tone header,

means connecting all said chi and no-ise gates to said chi and noise lheader.

15. An electronic organ having,

a gamut of continuously running tone oscillators tuned .according to the musical scale to provide tone components, j

a gamut of continuously running chi oscillators arranged each to provide a chi component for one of said tone components,

a chi gate connected in cascade with each of said chi oscillators,

a tone gate in cascade with each of said tone oscillators,

a source of keying voltage,

key operated means for applying said keying voltage concurrently to render conductive at will one of said tone gates and that one of said chi gates selected to provide a chi component for the tone component passed by said one of said tone gates.

16. The combination according to claim 15 wherein is provided a tone Ibus connected to only to all said tone gates and a chi bus connected only to all said chi gates.

17. The combination according to claim 15 wherein is provided a noise source associated with each of said chi oscillators,

means connecting each of said chi gates in cascade with one of said noise sources.

18. The combination according to claim 17 wherein is provided means for at will disabling all said noise sources without disabling said tone and chi oscillators.

19. The combination according to claim 17 wherein is provided means for at will disabling lall said chi oscillators without disabling said noise sources.

20. An electronic organ having a gamut of continuously running note oscillators arranged in pitch according to a musical scale,

a source of keying voltage,

-a plurality of chi oscillators,

a separate chi gate connected in cascade with each of said chi oscillators,

.a separate note gate connected in cascade with each of said note oscillators,

said note gates each including means for developing a note signal of relatively slow rise and relatively said note gates each includes slow ldecay in response immediately to application and removal of a keying voltage, respectively,

said chi gates each including means responsive immediately to :application of said keying voltage for developing a chi signal of relatively rapid rise to a peak value followed by immediate fall to a zero value.

21. The combination according to claim 20 wherein a solid state normally non-conductive diode gating cir cuit connected in series between one of said note oscillators `and a load,

wherein said chi gates each includes a solid state di- Iode normally non-conductive gating Vcircuit in series between one of said chi oscillators and a load.

22. The combination according to claim 21, wherein said chi gating circuits each further includes,

a capacitor having one terminal connected to a reference point,

a rst source of current of one polarity,

a resistance in series between said source and the other terminal of said capacitor, Y

a second source of current of polarity opposite to said one polarity connected to the other terminal of said capacitor,

said second source of current having a value decreasing as a function of time to an absolute Value lower than the labsolute value of said current of one polarity from an absolute value higher than the absolute value of said current of one polarity, and

a diode clamp shunted across said capacitor,

said diode having an electrode connected directly to said reference point.

23. The combination according to claim 1 wherein the said gates have eac-h a control point,

a source of negative D.C, voltage,

a plurality of resistors,

a circuit including one of said key switches and said plurality of resistors all connected in series between said source of negative D.C. Voltage and said control point,

a capacitor connected between a rst junction point of said resistors and ground,

a diode having its cathode connected to another junction point of said resistors,

additional capacitors,

said additional capacitors being connected in series between the anode of said diode and ground,

an additional resistor whose resistance is high as compared with any of said plurality of resistors,

said additional resistor connecting said anode to ground,

a source of positive D.C. voltage,

a further resistor -connecting said source of positive D.C. voltage to a junction of said additional capacitors,

a further diode for clamping said junction of said additional capacitors to ground and having its cathode connected to ground,

a Vcircuit including another further resistor connecting said junction of said additional capacitors to a control point of the second mentioned of said gates.

24. The combination according to claim 2, wherein the keying circuit for each key switch includes a first circuit which actuates the control point of the Iassociated one of said note gates,

a second circuit which is controlled by the energization `of said irst circuit and actuates the control point of the associated one of said chi gates, and

wherein said first circuit comprises a plurality of resistors, 'a source of negative D.C. voltage and said key switch all connected in series to said control point of said note gate,

a capacitor,

said capacitor being connected between a junction point of said resistors and ground,

a diode,

the cathode of said diode being connected to another junction point of said resistors,

an additional resistor whose resistance is high compared to any of said plurality of resistors,

the anode of said diode being connected to ground through said additional resistor.

25. The combination according to claim 24 wherein said second circuit comprises a second plurality of resistors, l

`a source of positive D.C. voltage,

said second plurality of resistors being connected in series between the control point of said chil gate and said positive D C. source,

a second capacitor connected between a junction of said second plurality of resistors and said anode of said diode,

a third capacitor connected between said junction lof said second plurality of resistors and ground and a second diode,

said second diode clamping said junction of said second plurality of resistors to ground and having its cathode connected to ground.

References Cited UNITED STATES PATENTS ARTHUR GAUSS, Primary Examiner. DAVID I. GALVIN, I. C. EDELL, Examiners, I. BUSCH, S. D.l MILLER, Assistant Examiners. 

1. IN AN ELECTRONIC ORGAN, A GAMUT OF TONE SOURCES, SAID TONE SOURCES CONSTITUTING CONTINUOUSLY RUNNING OSCILLATORS, AN OUTPUT DEVICE, GATES ASSOCIATED WITH EACH OF SAID SOURCES FOR GATING SAID TONES FROM SAID SOURCES TO SAID OUTPUT DEVICE, A KEYING CIRCUIT CONNECTED TO EACH OF SAID GATES, A KEY SWITCH ASSOCIATED WITH EACH OF SAID KEYING CIRCUITS, EACH OF SAID KEYING CIRCUITS GENERATING PAIRED GATING WAVES ON CLOSURE OF THE ASSOCIATED KEY SWITCH, ONE OF SAID GATING WAVES HAVING A SHAPE APPROPRIATE TO GRADUAL BUILD UP OF AN ORGAN TONE, THE OTHER OF SAID GATING WAVES HAVING A WAVE SHAPE APPROPRIATE TO A CLIFF COMPONENT OF A TONE AND MEANS FOR APPLYING THE ONE OF SAID GATING WAVES TO A GATE ASSOCIATED WITH A TONE OSCILLATOR HAVING A PREDETERMINED PITCH AND THE OTHER OF SAID GATING WAVES SIMULTANEOUSY TO A GATE ASSOCIATED WITH A TONE OSCILLATOR OF PITCH SUITABLE FOR PRO VIDING CHIFF COMPONENT FOR SAID PREDETERMINED PITCH.
 7. A KEYING CIRCUIT, INCLUDING A GATE HAVING A CONTROL POINT, A SOURCE OF NEGATIVE D.C. VOLTAGE, A SWITCH, AND SERIES RESISTANCES, ALL CONNECTED IN SERIER TO THE CONTROL POINT OF SAID GATE, A CAPACITOR CONNECTED BETWEEN A FIRST POINT JUNCTION OF SAID RESISTANCES AND GROUND, A DIODE HAVING ITS CATHODE CONNECTED TO ANOTHER JUNCTION POINT OF SAID RESISTANCES, ADDITIONAL CAPACITORS CONNECTED IN SERIES BETWEEN THE ANODE OF SAID DIODE AND GROUND, A RELATIVELY HIGH RESISTANCE CONNECTING SAID ANODE TO GROUND, A SOURCE OF POSITIVE D.C. VOLTAGE, A RESISTANCE CONNECTING SAID SOURCE OF POSITIVE D.C. VOLTAGE TO A JUNCTION OF SAID ADDITIONAL CAPACITORS, A FURTHER DIODE FOR CLAMPING SAID JUNCTION OF SAID ADDITIONAL CAPACITORS TO GROUND, SAID FURTHER DIODE HAVING ITS CATHODE DIRECTLY CONNECTED TO GROUND, A FURTHER GATE, AND A RESISTANCE CONNECTING THE ANODE OF SAID FURTHER DIODE TO A CONTROL POINT OF SAID FURTHER GATE.
 8. IN COMBINATION, A CAPACITOR HAVING ONE TERMINAL CONNECTED TO A REFERENCE POINT, A SOURCE OF POSITIVE CURRENT, A RESISTANCE IN SERIES BETWEEN SAID SOURCE AND THE OTHER TERMINAL OF SAID CAPACITOR, A SOURCE OF NEGATIVE CURRENT CONNECTED TO THE OTHER TERMINAL OF SAID CAPACITOR, SAID SOURCE OF NEGATIVE CURRENT HAVING A VALUE DECREASING AS A FUNCTION OF TIME TO AN ABSOLUTE VALUE LOWER THAN THE ABSOLUTE VALUE OF SAID POSITIVE CURRENT FROM AN ABSOLUTE VALVE HIGHER THAN THE ABSOLUTE VALUE OF SAID POSITIVE CURRENT, AND A DIODE CLAMP SHUNTED ACROSS SAID CAPACITOR, SAID DIODE CLAMP HAVING ITS CATHODE CONNECTED DIRECTLY TO SAID REFERENCE POINT. 